from django.conf import settings
from django.db import models


class Conversation(models.Model):
    """Stores a user's review-agent conversation shell."""

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="review_conversations",
    )
    title = models.CharField(max_length=120, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-updated_at", "-id"]

    def __str__(self) -> str:
        return self.title or f"对话 {self.pk}"


class Message(models.Model):
    """Stores one user or assistant message in a conversation."""

    class Role(models.TextChoices):
        USER = "user", "用户"
        ASSISTANT = "assistant", "助手"

    conversation = models.ForeignKey(
        Conversation,
        on_delete=models.CASCADE,
        related_name="messages",
    )
    role = models.CharField(max_length=20, choices=Role.choices)
    content = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["created_at", "id"]

    def __str__(self) -> str:
        return f"{self.get_role_display()} - {self.conversation_id}"


class FileAttachment(models.Model):
    """Stores an uploaded file version for one conversation."""

    class UploadStatus(models.TextChoices):
        UPLOADED = "uploaded", "已上传"
        BOUND = "bound", "已绑定"
        DELETED = "deleted", "已删除"

    conversation = models.ForeignKey(
        Conversation,
        on_delete=models.CASCADE,
        related_name="file_attachments",
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="review_file_attachments",
    )
    original_name = models.CharField(max_length=255)
    version_no = models.PositiveIntegerField(default=1)
    is_active = models.BooleanField(default=True)
    storage_path = models.CharField(max_length=500)
    file_size = models.BigIntegerField(default=0)
    content_type = models.CharField(max_length=120, blank=True, default="")
    upload_status = models.CharField(
        max_length=20,
        choices=UploadStatus.choices,
        default=UploadStatus.UPLOADED,
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "ra_file_attachment"
        ordering = ["-created_at", "-id"]
        constraints = [
            models.UniqueConstraint(
                fields=["conversation", "original_name", "version_no"],
                name="uq_ra_attachment_conv_name_version",
            )
        ]
        indexes = [
            models.Index(
                fields=["conversation", "created_at"],
                name="idx_ra_attachment_conv_created",
            ),
            models.Index(
                fields=["user", "created_at"],
                name="idx_ra_attachment_user_created",
            ),
            models.Index(
                fields=["conversation", "original_name", "is_active"],
                name="idx_ra_attachment_active",
            ),
        ]

    def __str__(self) -> str:
        return f"{self.original_name} v{self.version_no}"


class FileSummaryBatch(models.Model):
    """Tracks one automatic file inventory and page-count workflow run."""

    class Status(models.TextChoices):
        PENDING = "pending", "待执行"
        RUNNING = "running", "执行中"
        SUCCESS = "success", "成功"
        FAILED = "failed", "失败"

    conversation = models.ForeignKey(
        Conversation,
        on_delete=models.CASCADE,
        related_name="file_summary_batches",
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="review_file_summary_batches",
    )
    trigger_message = models.ForeignKey(
        Message,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="triggered_file_summary_batches",
    )
    batch_no = models.CharField(max_length=64, unique=True)
    product_name = models.CharField(max_length=200, blank=True, default="")
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.PENDING)
    total_files = models.IntegerField(default=0)
    supported_files = models.IntegerField(default=0)
    success_files = models.IntegerField(default=0)
    failed_files = models.IntegerField(default=0)
    unsupported_files = models.IntegerField(default=0)
    uncertain_files = models.IntegerField(default=0)
    total_pages = models.IntegerField(default=0)
    work_dir = models.CharField(max_length=500, blank=True, default="")
    error_message = models.TextField(blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)
    started_at = models.DateTimeField(null=True, blank=True)
    finished_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        db_table = "ra_file_summary_batch"
        ordering = ["-created_at", "-id"]
        indexes = [
            models.Index(fields=["conversation", "created_at"], name="idx_ra_batch_conv_created"),
            models.Index(fields=["user", "created_at"], name="idx_ra_batch_user_created"),
            models.Index(fields=["status", "created_at"], name="idx_ra_batch_status"),
        ]

    def __str__(self) -> str:
        return self.batch_no


class FileSummaryBatchAttachment(models.Model):
    """Binds a workflow batch to the exact attachment versions it uses."""

    class SourceRole(models.TextChoices):
        ARCHIVE = "archive", "压缩包"
        MULTI_FILE = "multi_file", "多文件"

    batch = models.ForeignKey(
        FileSummaryBatch,
        on_delete=models.CASCADE,
        related_name="batch_attachments",
    )
    attachment = models.ForeignKey(
        FileAttachment,
        on_delete=models.CASCADE,
        related_name="batch_bindings",
    )
    source_role = models.CharField(
        max_length=20,
        choices=SourceRole.choices,
        default=SourceRole.MULTI_FILE,
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "ra_file_summary_batch_attachment"
        constraints = [
            models.UniqueConstraint(
                fields=["batch", "attachment"],
                name="uq_ra_batch_attachment",
            )
        ]
        indexes = [
            models.Index(
                fields=["batch", "created_at"],
                name="idx_ra_batch_attachment_batch",
            ),
            models.Index(fields=["attachment"], name="idx_ra_batch_attach_file"),
        ]


class FileSummaryItem(models.Model):
    """Stores one scanned file and its page-count result."""

    class StatisticsStatus(models.TextChoices):
        SUCCESS = "success", "成功"
        FAILED = "failed", "失败"
        UNSUPPORTED = "unsupported", "不支持"
        UNCERTAIN = "uncertain", "不确定"
        SKIPPED = "skipped", "跳过"

    batch = models.ForeignKey(
        FileSummaryBatch,
        on_delete=models.CASCADE,
        related_name="items",
    )
    file_index = models.PositiveIntegerField()
    directory_level = models.CharField(max_length=300, blank=True, default="")
    file_name = models.CharField(max_length=255)
    file_type = models.CharField(max_length=20)
    relative_path = models.CharField(max_length=500)
    storage_path = models.CharField(max_length=500)
    page_count = models.IntegerField(null=True, blank=True)
    statistics_status = models.CharField(
        max_length=20,
        choices=StatisticsStatus.choices,
        default=StatisticsStatus.SKIPPED,
    )
    retry_count = models.PositiveIntegerField(default=0)
    error_message = models.TextField(blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "ra_file_summary_item"
        ordering = ["file_index", "id"]
        constraints = [
            models.UniqueConstraint(
                fields=["batch", "relative_path"],
                name="uq_ra_item_batch_relative_path",
            )
        ]
        indexes = [
            models.Index(fields=["batch", "file_index"], name="idx_ra_item_batch_index"),
            models.Index(fields=["batch", "statistics_status"], name="idx_ra_item_batch_status"),
            models.Index(fields=["batch", "file_type"], name="idx_ra_item_batch_type"),
        ]


class WorkflowNodeRun(models.Model):
    """Stores recoverable status for one workflow node."""

    class Status(models.TextChoices):
        PENDING = "pending", "等待中"
        RUNNING = "running", "执行中"
        RETRYING = "retrying", "重试中"
        SUCCESS = "success", "成功"
        FAILED = "failed", "失败"
        SKIPPED = "skipped", "跳过"

    batch = models.ForeignKey(
        FileSummaryBatch,
        on_delete=models.CASCADE,
        related_name="node_runs",
    )
    node_code = models.CharField(max_length=40)
    node_name = models.CharField(max_length=80)
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.PENDING)
    progress = models.PositiveIntegerField(default=0)
    message = models.TextField(blank=True, default="")
    started_at = models.DateTimeField(null=True, blank=True)
    finished_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        db_table = "ra_workflow_node_run"
        constraints = [
            models.UniqueConstraint(fields=["batch", "node_code"], name="uq_ra_node_batch_code")
        ]
        indexes = [
            models.Index(fields=["batch", "status"], name="idx_ra_node_batch_status"),
        ]


class WorkflowEvent(models.Model):
    """Persists workflow events for SSE replay and diagnostics."""

    batch = models.ForeignKey(
        FileSummaryBatch,
        on_delete=models.CASCADE,
        related_name="events",
    )
    event_type = models.CharField(max_length=40)
    payload = models.JSONField(default=dict)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "ra_workflow_event"
        ordering = ["id"]
        indexes = [
            models.Index(fields=["batch", "id"], name="idx_ra_event_batch_id"),
            models.Index(fields=["batch", "created_at"], name="idx_ra_event_batch_created"),
        ]


class ExportedSummaryFile(models.Model):
    """Stores generated report files for permission-checked download."""

    class ExportType(models.TextChoices):
        MARKDOWN = "markdown", "Markdown"
        EXCEL = "excel", "Excel"

    class Status(models.TextChoices):
        SUCCESS = "success", "成功"
        FAILED = "failed", "失败"

    batch = models.ForeignKey(
        FileSummaryBatch,
        on_delete=models.CASCADE,
        related_name="exports",
    )
    export_type = models.CharField(max_length=20, choices=ExportType.choices)
    file_name = models.CharField(max_length=255)
    storage_path = models.CharField(max_length=500)
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.SUCCESS)
    error_message = models.TextField(blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "ra_exported_summary_file"
        ordering = ["-created_at", "-id"]
        indexes = [
            models.Index(fields=["batch", "export_type"], name="idx_ra_export_batch_type"),
            models.Index(fields=["batch", "created_at"], name="idx_ra_export_batch_created"),
        ]